Targeted zinc-finger repressors to the oncogenic HBZ gene inhibit adult T-cell leukemia (ATL) proliferation

Human T-lymphotropic virus type I (HTLV-I) infects CD4+ T-cells resulting in a latent, life-long infection in patients. Crosstalk between oncogenic viral factors results in the transformation of the host cell into an aggressive cancer, adult T-cell leukemia/lymphoma (ATL). ATL has a poor prognosis with no currently available effective treatments, urging the development of novel therapeutic strategies. Recent evidence exploring those mechanisms contributing to ATL highlights the viral anti-sense gene HTLV-I bZIP factor (HBZ) as a tumor driver and a potential therapeutic target. In this work, a series of zinc-finger protein (ZFP) repressors were designed to target within the HTLV-I promoter that drives HBZ expression at highly conserved sites covering a wide range of HTLV-I genotypes. ZFPs were identified that potently suppressed HBZ expression and resulted in a significant reduction in the proliferation and viability of a patient-derived ATL cell line with the induction of cell cycle arrest and apoptosis. These data encourage the development of this novel ZFP strategy as a targeted modality to inhibit the molecular driver of ATL, a possible next-generation therapeutic for aggressive HTLV-I associated malignancies.

Harnessing Rift Valley fever virus NSs gene for cancer gene therapy

One of the greatest challenges in the treatment of cancer is tumor heterogeneity which results in differential responses to chemotherapy and drugs that work through a single pathway. A therapeutic agent that targets cancer cells for death through multiple mechanisms could be advantageous as a broad inhibitor for many types of cancers and the heterogeneous alterations they possess. Several viral proteins have been exploited for antiproliferative and apoptotic effect in cancer cells by disrupting critical survival pathways. Here, we report the use of the non-structural protein on the S segment (NSs) gene from the Rift Valley fever virus (RVFV) to induce cancer cell death. NSs has immune evasion functions in the context of RVFV with many of these functions affecting proliferation pathways and DNA damage signaling, which could be leveraged against cancer cells. We find that expression of NSs in multiple cancer cell lines leads to a rapid decline in cell viability and induction of apoptosis. Interestingly, we observed reduced toxicity in normal cells suggesting cancer cells may be more susceptible to NSs-mediated cell death. To enhance specificity of NSs for use in hepatocellular carcinoma, we incorporated four miR-122 binding sites in the 3' untranslated region (UTR) of the NSs mRNA to achieve cell type specific expression. Observations presented here collectively suggest that delivery of the NSs gene may provide a unique therapeutic approach in a broad range of cancers.

Engineered extracellular vesicles directed to the spike protein inhibit SARS-CoV-2

SARS-CoV-2 (CoV-2) viral infection results in COVID-19 disease, which has caused significant morbidity and mortality worldwide. A vaccine is crucial to curtail the spread of SARS-CoV-2, while therapeutics will be required to treat ongoing and reemerging infections of SARS-CoV-2 and COVID-19 disease. There are currently no commercially available effective anti-viral therapies for COVID-19, urging the development of novel modalities. Here, we describe a molecular therapy specifically targeted to neutralize SARS-CoV-2, which consists of extracellular vesicles (EVs) containing a novel fusion tetraspanin protein, CD63, embedded within an anti-CoV-2 nanobody. These anti-CoV-2-enriched EVs bind SARS-CoV-2 spike protein at the receptor-binding domain (RBD) site and can functionally neutralize SARS-CoV-2. This work demonstrates an innovative EV-targeting platform that can be employed to target and inhibit the early stages of SARS-CoV-2 infection.

Exosome-mediated stable epigenetic repression of HIV-1

Human Immunodeficiency Virus (HIV-1) produces a persistent latent infection. Control of HIV-1 using combination antiretroviral therapy (cART) comes at the cost of life-shortening side effects and development of drug-resistant HIV-1. An ideal and safer therapy should be deliverable in vivo and target the stable epigenetic repression of the virus, inducing a stable "block and lock" of virus expression. Towards this goal, we developed an HIV-1 promoter-targeting Zinc Finger Protein (ZFP-362) fused to active domains of DNA methyltransferase 3 A to induce long-term stable epigenetic repression of HIV-1. Cells were engineered to produce exosomes packaged with RNAs encoding this HIV-1 repressor protein. We find here that the repressor loaded anti-HIV-1 exosomes suppress virus expression and that this suppression is mechanistically driven by DNA methylation of HIV-1 in humanized NSG mouse models. The observations presented here pave the way for an exosome-mediated systemic delivery platform of therapeutic cargo to epigenetically repress HIV-1 infection.

A SARS-CoV-2 targeted siRNA-nanoparticle therapy for COVID-19

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in humans. Despite several emerging vaccines, there remains no verifiable therapeutic targeted specifically to the virus. Here we present a highly effective small interfering RNA (siRNA) therapeutic against SARS-CoV-2 infection using a novel lipid nanoparticle (LNP) delivery system. Multiple siRNAs targeting highly conserved regions of the SARS-CoV-2 virus were screened, and three candidate siRNAs emerged that effectively inhibit the virus by greater than 90% either alone or in combination with one another. We simultaneously developed and screened two novel LNP formulations for the delivery of these candidate siRNA therapeutics to the lungs, an organ that incurs immense damage during SARS-CoV-2 infection. Encapsulation of siRNAs in these LNPs followed by in vivo injection demonstrated robust repression of virus in the lungs and a pronounced survival advantage to the treated mice. Our LNP-siRNA approaches are scalable and can be administered upon the first sign of SARS-CoV-2 infection in humans. We suggest that an siRNA-LNP therapeutic approach could prove highly useful in treating COVID-19 disease as an adjunctive therapy to current vaccine strategies.

Abstract 2393: The systematic evaluation of the oncogenic lncRNA LINC00963 using a CRISPRScan technique

Long non-coding RNAs (LncRNAs) have been found to play important roles in maintaining and promoting cellular proliferation in cancerous cells. One such lncRNA, LINC00963 has been found to promote cellular proliferation, migration and tumorigenesis in prostate, ovarian, breast and non-small cell lung (NSCLC) cancer. In this study, we aim to identify important functional regions of this lncRNA with a view to identify unique regions for targeted drug therapy. In order to achieve this, we sought to investigate this lncRNA in the A549 NSCLC cell line. We found that LINC00963 was highly expressed and when targeted with either siRNAs or antisense oligonucleotides, cells rapidly undergo apoptosis. Using cell death as a proxy for loss-of-function, we characterized LINC00963 at the genomic level using a CRIPSRScan approach. CRISPRScan is a novel way of determining lncRNA functional domains through the introduction of local mutations. These mutations could potentially disrupt lncRNA function, which for LINC00963 would lead to apoptosis of the cell. We created a unique lentivirus library comprised of 1784 single guide RNAs spanning the length of LINC00963 in order to precisely identify regions of functional importance. Upon transduction in a stably expressing Cas9-A549 cell line, we collected cellular fractions over time, and using high-throughput sequencing (NextSeq, Illumina), evaluated the depletion of these sgRNAs as a proxy for their importance in LINC00963 function. The identification of these key genomic regions that may render LINC00963 non-functional may offer new lncRNA target sites for anti-cancer therapies in the future. Additionally, the utilization of an in-depth CRISPR-Cas9 approach to determine important lncRNA domains provides a novel and precise way in which to evaluate lncRNA function.

Citation Format: Roslyn M. Ray, Lu Lang, Sheela P. Pokharel, Denis O'Meally, Tristan A. Scott, Chun-Wei Chen, Kevin V. Morris. The systematic evaluation of the oncogenic lncRNA LINC00963 using a CRISPRScan technique [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2393.

A SARS-CoV-2 targeted siRNA-nanoparticle therapy for COVID-19

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in humans. Despite several emerging vaccines, there remains no verifiable therapeutic targeted specifically to the virus. Here we present a highly effective siRNA therapeutic against SARS-CoV-2 infection using a novel lipid nanoparticle delivery system. Multiple small-interfering RNAs (siRNAs) targeting highly conserved regions of the SARS-CoV-2 virus were screened and three candidate siRNAs emerged that effectively inhibit virus by greater than 90% either alone or in combination with one another. We simultaneously developed and screened two novel lipid nanoparticle formulations for the delivery of these candidate siRNA therapeutics to the lungs, an organ that incurs immense damage during SARS-CoV-2 infection. Encapsulation of siRNAs in these LNPs followed by in vivo injection demonstrated robust repression of virus in the lungs and a pronounced survival advantage to the treated mice. Our LNP-siRNA approaches are scalable and can be administered upon the first sign of SARS-CoV-2 infection in humans. We suggest that an siRNA-LNP therapeutic approach could prove highly useful in treating COVID-19 disease as an adjunctive therapy to current vaccine strategies.

Broadly active zinc finger protein-guided transcriptional activation of HIV-1

Human immunodeficiency virus type 1 (HIV-1) causes a persistent viral infection resulting in the demise of immune regulatory cells. Clearance of HIV-1 infection results in integration of proviral DNA into the genome of host cells, which provides a means for evasion and long-term persistence. A therapeutic compound that specifically targets and sustainably activates a latent HIV-1 provirus could be transformative and is the goal for the "shock-and-kill" approach to a functional cure for HIV-1. Substantial progress has been made toward the development of recombinant proteins that target specific genomic loci for gene activation, repression, or inactivation by directed mutations. However, most of these modalities are too large or too complex for efficient therapeutic application. We describe here the development and testing of a novel recombinant zinc finger protein transactivator, ZFP-362-VPR, which specifically and potently enhances proviral HIV-1 transcription both in established latency models and activity across different viral clades. Additionally, ZFP-362-VPR-activated HIV-1 reporter gene expression in a well-established primary human CD4+ T cell latency model and off-target pathways were determined by transcriptome analyses. This study provides clear proof of concept for the application of a novel, therapeutically relevant, protein transactivator to purge cellular reservoirs of HIV-1.

Designer nucleases to treat malignant cancers driven by viral oncogenes

Viral oncogenic transformation of healthy cells into a malignant state is a well-established phenomenon but took decades from the discovery of tumor-associated viruses to their accepted and established roles in oncogenesis. Viruses cause ~ 15% of know cancers and represents a significant global health burden. Beyond simply causing cellular transformation into a malignant form, a number of these cancers are augmented by a subset of viral factors that significantly enhance the tumor phenotype and, in some cases, are locked in a state of oncogenic addiction, and substantial research has elucidated the mechanisms in these cancers providing a rationale for targeted inactivation of the viral components as a treatment strategy. In many of these virus-associated cancers, the prognosis remains extremely poor, and novel drug approaches are urgently needed. Unlike non-specific small-molecule drug screens or the broad-acting toxic effects of chemo- and radiation therapy, the age of designer nucleases permits a rational approach to inactivating disease-causing targets, allowing for permanent inactivation of viral elements to inhibit tumorigenesis with growing evidence to support their efficacy in this role. Although many challenges remain for the clinical application of designer nucleases towards viral oncogenes; the uniqueness and clear molecular mechanism of these targets, combined with the distinct advantages of specific and permanent inactivation by nucleases, argues for their development as next-generation treatments for this aggressive group of cancers.

AAV-Mediated Expression of Broadly Neutralizing and Vaccine-like Antibodies Targeting the HIV-1 Envelope V2 Region

HIV-1 infection continues to be a global health challenge and a vaccine is urgently needed. Broadly neutralizing antibodies (bNAbs) are considered essential as they inhibit multiple HIV-1 strains, but they are difficult to elicit by conventional immunization. In contrast, non-neutralizing antibodies that correlated with reduced risk of infection in the RV144 HIV vaccine trial are relatively easy to induce, but responses are not durable. To overcome these obstacles, adeno-associated virus (AAV) vectors were used to provide long-term expression of antibodies targeting the V2 region of the HIV-1 envelope protein, including the potent CAP256-VRC26.25 bNAb, as well as non-neutralizing CAP228 antibodies that resemble those elicited by vaccination. AAVs mediated effective antibody expression in cell culture and immunocompetent mice. Mean concentrations of human immunoglobulin G (IgG) in mouse sera increased rapidly following a single AAV injection, reaching 8–60 μg/mL for CAP256 antibodies and 44–220 μg/mL for CAP228 antibodies over 24 weeks, but antibody concentrations varied for individual mice. Secreted antibodies collected from serum retained the expected binding and neutralizing activity. The vectors generated here are, therefore, suitable for the delivery of V2-targeting HIV antibodies, and they could be used in a vectored immunoprophylaxis (VIP) approach to sustain the level of antibody expression required to prevent HIV infection.

Effect of transcription inhibition and generation of suppressive viral non-coding RNAs

Background

HIV-1 patients receiving combination antiretroviral therapy (cART) survive infection but require life-long adherence at high expense. In chronic cART-treated patients with undetectable viral titers, cell-associated viral RNA is still detectable, pointing to low-level viral transcriptional leakiness. To date, there are no FDA-approved drugs against HIV-1 transcription. We have previously shown that F07#13, a third generation Tat peptide mimetic with competitive activity against Cdk9/T1-Tat binding sites, inhibits HIV-1 transcription in vitro and in vivo.

Results

Here, we demonstrate that increasing concentrations of F07#13 (0.01, 0.1, 1 µM) cause a decrease in Tat levels in a dose-dependent manner by inhibiting the Cdk9/T1-Tat complex formation and subsequent ubiquitin-mediated Tat sequestration and degradation. Our data indicate that complexes I and IV contain distinct patterns of ubiquitinated Tat and that transcriptional inhibition induced by F07#13 causes an overall reduction in Tat levels. This reduction may be triggered by F07#13 but ultimately is mediated by TAR-gag viral RNAs that bind suppressive transcription factors (similar to 7SK, NRON, HOTAIR, and Xist lncRNAs) to enhance transcriptional gene silencing and latency. These RNAs complex with PRC2, Sin3A, and Cul4B, resulting in epigenetic modifications. Finally, we observed an F07#13-mediated decrease of viral burden by targeting the R region of the long terminal repeat (HIV-1 promoter region, LTR), promoting both paused polymerases and increased efficiency of CRISPR/Cas9 editing in infected cells. This implies that gene editing may be best performed under a repressed transcriptional state.

Conclusions

Collectively, our results indicate that F07#13, which can terminate RNA Polymerase II at distinct sites, can generate scaffold RNAs, which may assemble into specific sets of “RNA Machines” that contribute to gene regulation. It remains to be seen whether these effects can also be seen in various clades that have varying promoter strength, mutant LTRs, and in patient samples.

Electronic supplementary material

The online version of this article (10.1186/s12977-019-0475-0) contains supplementary material, which is available to authorized users.

Long Non-Coding RNA Modulation of VEGF-A during Hypoxia

The role and function of long non-coding RNAs (lncRNAs) in modulating gene expression is becoming apparent. Vascular endothelial growth factor A (VEGF-A) is a key regulator of blood vessel formation and maintenance making it a promising therapeutic target for activation in ischemic diseases. In this study, we uncover a functional role for two antisense VEGF-A lncRNAs, RP1-261G23.7 and EST AV731492, in transcriptional regulation of VEGF-A during hypoxia. We find here that both lncRNAs are polyadenylated, concordantly upregulated with VEGF-A, localize to the VEGF-A promoter and upstream elements in a hypoxia dependent manner either as a single-stranded RNA or DNA bound RNA, and are associated with enhancer marks H3K27ac and H3K9ac. Collectively, these data suggest that VEGF-A antisense lncRNAs, RP1-261G23.7 and EST AV731492, function as VEGF-A promoter enhancer-like elements, possibly by acting as a local scaffolding for proteins and also small RNAs to tether.

Potent and Targeted Activation of Latent HIV-1 Using the CRISPR/dCas9 Activator Complex

HIV-1 provirus integration results in a persistent latently infected reservoir that is recalcitrant to combined antiretroviral therapy (cART) with lifelong treatment being the only option. The "shock and kill" strategy aims to eradicate latent HIV by reactivating proviral gene expression in the context of cART treatment. Gene-specific transcriptional activation can be achieved using the RNA-guided CRISPR-Cas9 system comprising single guide RNAs (sgRNAs) with a nuclease-deficient Cas9 mutant (dCas9) fused to the VP64 transactivation domain (dCas9-VP64). We engineered this system to target 23 sites within the long terminal repeat promoter of HIV-1 and identified a "hotspot" for activation within the viral enhancer sequence. Activating sgRNAs transcriptionally modulated the latent proviral genome across multiple different in vitro latency cell models including T cells comprising a clonally integrated mCherry-IRES-Tat (LChIT) latency system. We detected consistent and effective activation of latent virus mediated by activator sgRNAs, whereas latency reversal agents produced variable activation responses. Transcriptomic analysis revealed dCas9-VP64/sgRNAs to be highly specific, while the well-characterized chemical activator TNFα induced widespread gene dysregulation. CRISPR-mediated gene activation represents a novel system which provides enhanced efficiency and specificity in a targeted latency reactivation strategy and represents a promising approach to a "functional cure" of HIV/AIDS.

Effects of wheat distillers dried grains with solubles with or without protease and β-mannanase on the performance of turkey hen poults

Expansion in bioethanol production has resulted in distillers dried grains with solubles (DDGS) being readily available as a major protein source in the poultry industry. Two experiments were conducted to investigate effects of wheat DDGS (wDDGS) and enzyme on nutrient digestibility and performance of turkey hen poults (7 to 21 d). Two starter diets (0 or 30% wDDGS) were formulated to meet or exceed the nutrient requirements for Hybrid Converter female turkeys. These diets were then mixed in different proportions to obtain 2 additional wDDGS inclusion levels (10 and 20%). In Experiment 1, 0 and 30% wDDGS diets were each subdivided into 3 portions and supplemented with no enzyme (E-), protease (P+; 0.125 g/kg) or β-mannanase (M+; 0.5 g/kg). A total of 144, 7-day-old poults were randomly distributed in groups of 4 in 6 replicate cages per treatment. There were no significant main effects or interactions on feed intake from 7 to 21 d. However, a positive (P<0.05) effect of 30% wDDGS was shown for weight gain and gain:feed. A significant interaction on nitrogen retention (NR) was found between enzymes and wDDGS level. There were significant main effects and interactions on the AME of the diets. The AME was higher (P<0.05) for 30% compared to 0% wDDGS. Supplementation of P+ decreased (P<0.05) AME for 0% diets as compared to 30% diets and vice versa for M+. In Experiment 2, 7-day-old poults (4 birds per 6 replications per treatment) were fed 4 levels of wDDGS (0, 10, 20, and 30%) with no enzyme. A linear (P<0.01) response was found for gain:feed with 30% wDDGS having a better response. Quadratic (P<0.01) responses were also found for NR and AME; both were highest for 10% wDDGS diets. In summary, no beneficial effects of P+ or M+ were demonstrated in diets containing 30% wDDGS. Wheat DDGS is a valuable energy source and as high as 30% can be incorporated in turkey hen poults (7 to 21 d) diets.

Evaluation of inclusion level of wheat distillers dried grains with solubles with and without protease or β-mannanase on performance and water intake of turkey hens

It is becoming a common practice to use higher levels of wheat distillers dried grains with solubles (wDDGS) in poultry diets. The objective of this study was to determine the effects of level of inclusion of wDDGS with or without enzyme (E-, i.e., wDDGSE-) supplementation on performance and water consumption of turkey hens (0 to 72 d). Two diets (0 or 30% wDDGS) were formulated to meet the nutrient requirements of Hybrid Converter turkeys. Diets (0 or 30% wDDGS; starter, grower, and finisher) were then blended to obtain a different level of inclusion (15%) of wDDGS. The 30% wDDGS diet was divided into 3 fractions and 2 fractions supplemented with either protease (P+, i.e., wDDGSP+; 0.126 g/kg) or β-mannanase (M+, i.e., wDDGSM+; 0.05 g/kg). All 5 diets were fed ad libitum as mash. The 700 0-d turkey hens were randomly allocated into groups of 35 birds per replicate with 4 replicate floor pens per treatment, in a completely randomized design. Water consumption per pen was recorded beginning at 7 d. There was no effect of dietary treatment on feed intake. BW of turkey hens (52 d; grower) was significantly higher for 30% wDDGSP+ as compared to 0% wDDGSE- or 15% wDDGSE- diets; but was not different from 30% wDDGSE- or 30% wDDGSM+ diets. FCR (P < 0.01; 28 to 52 d), and total FCR (P < 0.05; 0 to 72 d) was significantly improved for birds fed 15 or 30% wDDGS regardless of enzyme treatment compared to 0% wDDGSE-. Water intake (WI, in mL per bird per day) tended to be higher (P = 0.08) between 7 and 28 d for 30% wDDGSP+ diets compared to other treatments. Similarly, WI of birds fed 30% wDDGSP+ was higher (P < 0.05; 28 to 52 and 52 to 72 d) and total WI (P = 0.07; 7 to 72 d) tended to be higher than other treatments. This study is the first to report the impact of wDDGS on WI. As high as 30% wDDGS can be substituted in turkey hen diets. No effect of P+ or M+ at the inclusion level tested was found on performance.

The effects of extrusion of wheat distillers dried grains with solubles with or without an enzyme cocktail on performance of turkey hen poults

Two experiments were conducted to determine if extrusion (EX) or enzymes (E) could overcome the restrictions (e.g., high fiber) of feeding wheat distillers dried grain with solubles (wDDGS) and improve its nutritional value for feeding turkeys. Two starter diets with either 0 or 30% wDDGS were formulated to meet or exceed the nutrient requirements of the Hybrid Converter female turkeys. The 30% wDDGS diet was substituted with either non-extruded (EX-) or extruded (EX+) wDDGS to produce three basal diets [0% wDDGS (EX-) or 30% wDDGS (EX-/EX+)]. Diets were blended to obtain 15% wDDGS. In the respective treatments, only wDDGS was extruded (temperature; 118°C, retention; 15 sec, total moisture; 25% and pressure 33 bar). The respective experimental diets were supplemented with/without an enzyme cocktail (E; 0.5 g/kg). Test diets were fed from 7-21 d in a completely randomized design. In Experiment 1, a total of 210 turkey hen poults were fed diets containing 0, 15, or 30% wDDGS (EX-) with or without enzyme (E+/E-). Body weight (BW) and feed intake (FI) were significantly higher for 0% wDDGSE-. Nitrogen retention (NR) and apparent metabolizable energy (AME) for the 30% wDDGSE- was significantly higher than other treatments at 21 d. The results indicated significant main effects of E and an interaction between wDDGS level and E. In Experiment 2, 280 turkey hen poults were fed 8 diets [15/30% wDDGS (E+/E-), (EX-/EX+)]. The level of wDDGS had a significant effect on BW, FI and gain:feed; 15% inclusion was superior to 30%. There were significant 2- and 3-way interactions for AME and NR at 21 d due to differences in enzyme response with 15 or 30% wDDGS inclusion and/or extrusion of wDDGS. As high as 15% wDDGS can be incorporated in turkey hen diets. There were no beneficial effects of EX or E on poult performance.

Factors related to medical appointment attendance after childbirth among HIV-infected women in the Paris region

This study examined factors related to medical appointment attendance after childbirth among HIV-infected women in the Paris region. We hypothesized that despite regular utilization of prenatal care, many women may not attend medical appointments after delivery for their own HIV infection. This was an observational cohort study of HIV-seropositive women delivering in four Paris hospitals in 2001. Follow-up attendance through 24 months after delivery was defined as 'regular' for women who had > or =4 HIV visits during the period, 'irregular' for <4 visits in the 24-months period and/or a gap between two visits >12 months, and 'no attendance' when < or =1 visit in the 2-year period. Of 169 women enrolled, 125 (75%) had regular attendance, 24 (14%) had irregular attendance, and 18 (11%) had no attendance. Multivariate analysis found the greater number of HIV visits during pregnancy and the prescription of combination therapy (versus zidovudine monotherapy) during pregnancy to be significantly related to regular attendance. Of the 18 women who had no attendance, 8 women (47%) continued to attend regular paediatric appointments with their infants during the 24-month period. Scheduling more frequent HIV visits during pregnancy may establish a pattern that will improve attendance during the post-partum period. In addition, increased communication between the health care providers of the mother and child may increase appointment attendance following delivery.

Second-trimester intra-abdominal bowel dilation in fetuses with gastroschisis predicts neonatal bowel atresia

OBJECTIVE

To determine in fetuses with gastroschisis the association between intra-abdominal bowel dilation in the second trimester and neonatal bowel atresia.

METHODS

We reviewed ultrasound and medical records of fetuses with gastroschisis from January 1998 to August 2004. Fetuses with intra-abdominal bowel dilation in the second trimester were identified and followed into the neonatal period.

RESULTS

We identified 58 mother-infant pairs showing fetal gastroschisis, with at least one prenatal ultrasound at our hospital and which were delivered there, or were transported there as newborns. Forty-eight of the 58 fetuses had no intra-abdominal bowel dilation and none of these neonates had bowel atresia. Ten of the 58 fetuses had intra-abdominal bowel dilation and all had bowel atresia at birth (P<0.0001). In eight cases in which ultrasound was performed at <25 weeks' gestation, intra-abdominal bowel dilation was already present.

CONCLUSION

Intra-abdominal bowel dilation in the second trimester predicts neonatal bowel atresia in fetuses with gastroschisis.

A Study on the Interaction of Xylanase and Phytase Enzymes in Wheat-Based Diets Fed to Commercial White and Brown Egg Laying Hens

A trial was conducted to investigate potential interactions between phytase and xylanase enzymes in wheat-based laying diets. Hens (480 ISA-White and 480 ISA-Brown) were distributed into 160 experimental units and fed one of 10 diets containing 75 to 77% wheat from 33 to 64 wk of age with a diet change at 49 wk. Two diets were adequate in P content (0.3 and 0.25% available P in the 2 phases) with or without xylanase (0 or 2,000 U/kg; Avizyme 2300, Danisco Animal Nutrition, Marlborough, Wiltshire, United Kingdom), and 8 diets had reduced P (0.2 and 0.15% available P) with or without xylanase and phytase (0, 300, 500, and 700 ppu/kg; Phyzyme 5000G, Danisco Animal Nutrition). Egg production was higher for ISA-Brown than for ISA-White hens, and ISA-Brown hens were larger. Eggs from ISA-Brown hens had lower albumen height; higher egg, shell, and albumen weights; and lower yolk weight than those from ISA-White hens. Egg production was not affected by the diet. In P-reduced diets without xylanase, phytase significantly increased BW gain in the first period with no change in feed intake or feed efficiency. In P-adequate diets, xylanase increased egg and albumen weight and albumen height. In P-reduced diets with xylanase, increasing levels of phytase increased egg and albumen weight. This trial demonstrated no negative interactions between these enzymes for production traits and no interactions between the diet and strain of hen. These data suggest that poultry producers can use these enzymes individually or together in feed for the Brown and White egg layers used in this study without concern for the strain of hen.

Genetic mutations in surfactant protein C are a rare cause of sporadic cases of IPF

BACKGROUND

While idiopathic pulmonary fibrosis (IPF) is one of the most common forms of interstitial lung disease, the aetiology of IPF is poorly understood. Familial cases of pulmonary fibrosis suggest a genetic basis for some forms of the disease. Recent reports have linked genetic mutations in surfactant protein C (SFTPC) with familial forms of pulmonary fibrosis, including one large family in which a number of family members were diagnosed with usual interstitial pneumonitis (UIP), the pathological correlate to IPF. Because of this finding in familial cases of pulmonary fibrosis, we searched for SFTPC mutations in a cohort of sporadic cases of UIP and non-specific interstitial pneumonitis (NSIP).

METHODS

The gene for SFTPC was sequenced in 89 patients diagnosed with UIP, 46 patients with NSIP, and 104 normal controls.

RESULTS

Ten single nucleotide polymorphisms in the SFTPC sequence were found in IPF patients and not in controls. Only one of these created an exonic change resulting in a change in amino acid sequence. In this case, a T to C substitution resulted in a change in amino acid 73 of the precursor protein from isoleucine to threonine. Of the remaining polymorphisms, one was in the 5' UTR, two were exonic without predicted amino acid sequence changes, and six were intronic. One intronic mutation suggested a potential enhancement of a splicing site.

CONCLUSIONS

Mutations in SFTPC are identified infrequently in this patient population. These findings indicate that SFTPC mutations do not contribute to the pathogenesis of IPF in the majority of sporadic cases.

The effect of phytase enzyme and level on nutrient extraction by broilers

Three experimental phytase enzyme preparations derived from the same Escherichia coli gene but produced in Saccharomyces cerevisiae (A), Pichia pastoris (B), and Pseudomonas fluorescens (C) were compared with a commercial enzyme preparation by addition to wheat-soybean meal diets fed to broiler chicks. A positive control diet contained sufficient available phosphorus for normal broiler growth and a negative control diet was phosphorus deficient. The 4 enzymes were added to the negative control diet at 3 levels each (150, 450, and 1,250 U/kg), and all diets were pelleted above 80 degrees C. Broiler chicks were fed experimental diets from 4 to 21 d. Chick performance and nutrient digestibility showed that the pel leting process inactivated enzymes A and C and the commercial enzyme. When added to the negative control diet, enzyme B had positive effects on broiler performance and calcium and phosphorus digestibility, and increasing levels of enzyme had greater positive effects. Enzyme B also increased the AME and protein digestibility over those of either control diet. These results suggest that enzyme B was not inactivated by pelleting above 80 degrees C, whereas the other enzymes were.

Effect of storage and layer age on quality of eggs from two lines of hens

Eggs from ISA-White and ISA-Brown hens between 28 and 59 wk of age were stored for up to 10 d to produce a sample of 5,763 eggs differing in the three major determinants of albumen quality. Eggs from ISA-Brown hens were larger and had less yolk, more albumen, and a greater percentage of shell than those from ISA-White hens. Egg size increased with increasing age of the hen, although more for the ISA-White hens than the ISA-Brown hens, and the yolk increased more in size than did the shell and albumen. During storage, albumen weight decreased and yolk weight increased slightly. The height of the inner thick albumen of eggs from ISA-White hens was greater than that of eggs from ISA-Brown hens, and it decreased as the hen age increased and with increasing time in storage. The pH of the albumen was not different between strains, and the effect of hen age was small, but it increased with time in storage. Regression coefficients of the height of the inner thick albumen on the weight of the egg were between -0.058 and 0.102, showing that the fixed regression of 0.05-mm albumen height per gram of egg implied by the Haugh unit is wrong. The statistical association between albumen pH and egg weight was very low. If albumen quality is being used as a measure of freshness, then the albumen height is biased by the strain and age of hen, whereas the albumen pH is not.

The effect of storage and strain of hen on egg quality

Eggs from 31-wk-old ISA-White and ISA-Brown hens were sampled immediately after lay and after periods of storage of 1, 3, 5, and 10 d at room temperature. Longer periods of storage resulted in lower albumen weight and albumen height and higher albumen pH. Eggs from ISA-Brown hens had more albumen and shell than those from ISA-White hens, likely due to differences in selection history rather than due to pleiotropic effects of eggshell color. Within each line and storage period, the egg weight was more closely associated with albumen weight than with yolk or shell weight. The albumen height of eggs from ISA-Brown hens was lower than that of ISA-White hens at all storage times, but the albumen pH was not affected by the strain. Albumen height and albumen pH were statistically unrelated in fresh eggs, but the association became larger as the storage period increased, suggesting that albumen height measures factors that are present when the egg is laid and changes during storage, whereas albumen pH measures only the effect of storage.

The effect of phosphorus, phytase enzyme, and calcium on the performance of layers fed corn-based diets

An experiment employing a factorial arrangement of two levels of Ca, two levels of available P (AP), and three levels of phytase enzyme was carried out with 360 ISA White layers from 18 to 67 wk of age. The Ca levels were maintained at 3.7 and 4.0% throughout the experiment. The AP levels were 0.2 and 0.4% for the high and low treatments until 55 wk of age and were reduced to 0.11 and 0.22% thereafter. Phytase enzyme levels were 0, 250, and 500 phytase units (FTU)/kg of feed. In the period before Week 55, either level of AP was likely adequate for maximum production. However, when lower levels of AP were fed after this time, low AP was associated with reduced BW and egg production, and enzyme supplementation was able to compensate for low AP. In this period, high AP and the highest level of phytase produced negative effects on BW, egg weight, and the feed conversion ratio. The ratio of Ca to AP was important; shell quality was best with high or low levels of both. With high levels of Ca, enzyme supplementation compensated for low levels of AP and overcompensated with a high level of AP. These effects were reduced or absent with low levels of Ca. It is clear from this study that phytase enzyme can compensate for low levels of AP in diets based on corn and soybean meal, but that the optimum level of supplementation depends as well on the Ca level.

Using acid insoluble ash marker ratios (diet:digesta) to predict digestibility of wheat and barley metabolizable energy and nitrogen retention in broiler chicks

Routine bioassay measurements of AME or N retention of broiler diets require measurements of gross energy (GE) or N and an acid insoluble ash marker in diet, excreta, or ileal digesta. These measurements of GE and N are time-consuming and expensive in comparison to measurements of added or natural occurring levels of acid insoluble ash. Data from bioassay measurements of AME and N retention of 138 wheat and 97 barley samples (with or without enzyme) were used to develop prediction equations relying on measurements of one that uses acid insoluble ash of diet, excreta or ileal digesta and GE and N of diet only; and a second equation using only acid insoluble ash of diet, excreta, or ileal digesta. The prediction equations demonstrate that part of or all of routine bomb calorimetry measurements for GE used to determine AME of wheat- or barley-based diets could be eliminated if a prediction error of 80 kcal/kg ME or less were acceptable. The prediction of N retention as compared to AME, based in part or totally on acid insoluble ash measurements, was less accurate; the prediction errors were equal to 2.3 and 6.5% for wheat- and barley-based diets, respectively. Ongoing research to improve the determination (speed, ease, and accuracy) of acid insoluble ash could provide a useful method to assess feeding value of ingredients and commercial poultry diets.

A broiler chick bioassay for measuring the feeding value of wheat and barley in complete diets

Energy is an important component of poultry feed and is derived principally from cereal grains. Unfortunately, all of the chemical energy is not available to the bird, and biological assays must be used to determine the digestible energy value of a cereal grain. The bioassay described uses four pens of six male broiler chicks, complete diets containing 80% of a test cereal grain (with or without an appropriate commercial enzyme), and ad libitum feed intake. Apparent metabolizable energy values (kilocalories per kilogram of cereal grain, DM basis) values are calculated from gross energy and acid insoluble ash measurements of diet and excreta collected for 24 h at 16 d of age. To monitor variation between broiler chick assays, due to bird, environment, etc., common control samples of Hard Red Spring (HRS) and Canadian Prairie Spring (CPS) wheat were tested in each of 15 separate assays over 2 yr. Similarly, for barley, control samples of hulled and hulless barley were repeatedly tested in five assays. Broiler performance in this study was lower than expected for commercial broilers, in part due to a high dietary cereal grain component and the fine mash texture. However, AME values as determined were comparable to those reported in the literature for wheat and barley. The CV for AME measured among pens, representing the intra-assay CV, was between 1.2 and 3.4% and was lower with enzyme supplementation. The interassay CV was only slightly higher than the intra-assay CV. This assay provides precise estimations of ME in cereal grains fed to young broilers that can be used for diet formulation or for verification of laboratory measures of feeding value of cereal grains.

Comparison of sample source (excreta or ileal digesta) and age of broiler chick on measurement of apparent digestible energy of wheat and barley

The broiler chick bioassay measures AME of wheat- or barley-based diets, with or without an enzyme, from excreta (24-h collections at 8 or 16 d) and ileal digesta (17 d). The objective was to discuss the merits and accuracy of sample source (excreta vs ileal digesta) and bird age for determining the feeding value of wheat and barley. The bioassay utilized 80% of a test cereal grain, 20% basal diet containing 1.1% acid insoluble ash marker, and fed with or without an enzyme to four pens of six male broilers from 4 to 17 d. A total of 138 wheat and 97 barley samples (with and without an enzyme) were tested in 15 and five bioassays, respectively. Within each wheat or barley bioassay two control wheat and barley samples were measured. The among-pens and between-assays CV for AME were calculated for these control samples, and correlation coefficients between the measures were calculated for the controls and for all of the 138 wheat and 97 barley samples included in the assays. For wheat samples, values for AME were lowest for excreta samples collected at 8 d, and similar for excreta and ileal digesta samples collected at 16 and 17 d, respectively. For barley samples, the three values were significantly different. The among-pens and between-assay CV were low for AME among both wheat and barley samples. Correlation coefficients between several measures of AME at 8 and 16 d were significant for the control samples with enzyme supplementation. When all samples were included in the analysis, correlation coefficients between AME measures were moderate to high. On the basis of accuracy, precision, and cost, these data favor measuring AME on excreta samples at 16 d of age. Comparisons of number of pens of broilers used to determine AME would suggest that much of the variability predicted with four pens of six broilers each could be achieved with three, and possibly two pens of six broilers each, thereby greatly increasing the capacity of the assay to screen large numbers of samples.

Comparison of bioabsorbable laminar bone membrane and non-resorbable ePTFE membrane in mandibular furcations

The purpose of the study was to compare clinical parameter changes and osseous regeneration in 12 pairs of comparable Class II mandibular molar furcation invasion defects using either a bioabsorbable demineralized laminar bone allograft membrane or a non-resorbable expanded polytetrafluoroethylene (ePTFE) membrane as a barrier in guided tissue regeneration. Measurements with calibrated periodontal probes were made to determine soft tissue recession, probing depth, and attachment levels. Defects within each pair were randomly selected for treatment with either bioabsorbable demineralized bone allograft membrane or ePTFE membrane. All defects were concurrently grafted with particulate demineralized freeze-dried bone allograft (DFDBA). Additional measurements were made at surgery to determine crestal resorption and the vertical and horizontal dimensions of the osseous defects. The temporal course and extent of membrane exposures were also recorded. The non-resorbable membrane was retrieved 6 weeks following placement. Six months following initial surgical treatment, each site was surgically re-entered and all soft and hard tissue measurements repeated. Descriptive statistical analysis revealed that both treatments resulted in significant within-group mean vertical and horizontal osseous fill, but no statistical difference emerged between the groups. As based on this pilot study, laminar bone membrane may be as effective as ePTFE when used in conjunction with DFDBA for treatment of Class II mandibular molar furcation bone defects. This pilot study of low power suggests that these two materials may be equivalent when used in conjunction with DFDBA. Further studies of much higher power and of the laminar bone alone as compared to positive and negative controls are required. Laminar bone does not require a secondary surgical procedure for removal and may undergo less frequent instances and degrees of exposure during healing.

Comparison of inert markers [chromic oxide or insoluble ash (Celite)] for determining apparent metabolizable energy of wheat- or barley-based broiler diets with or without enzymes

A broiler chick bioassay was used to measure the effect of two inert digestibility markers on the determination of dietary AME. Diets contained 80% of either wheat or barley (with or without enzyme) and either chromic oxide at 0.5% or one of three levels of insoluble ash (0.5, 1.0, or 1.5%) as markers. The various cereal and marker diet combinations were consumed ad libitum (0 to 21 d) by two groups of 10 male broilers in each of two trials. The AME of each diet was determined by measuring the respective marker ratios between diet and excreta (collected for 24 h at 7 or 21 d) or ileal digesta collected at 21 d. Growth and feed conversion were measured on each group of birds between 0 and 21 d. There was no effect of marker on growth or feed efficiency. However, determination of AME of wheat- or barley-based diets with or without enzymes were affected by choice of marker and whether markers were measured in excreta (7 or 21 d) or ileal digesta. Chromic oxide was viewed as the least accurate method for determining AME, based on chronic oxide's inability to define AME differences between barley-based diets with and without enzymes, whereas insoluble ash clearly demonstrated improved AME of wheat- and barley-based diets with an enzyme. The optimum levels of insoluble ash for accuracy and repeatability were between 0.5 and 1.0%. The AME of the diets were, on average, 5% lower when determined with 7 vs 21 d excreta and 2.5% lower for ileal digesta than excreta collected at 21 d. It was concluded that identification of components that result in variability in AME levels of diets will be improved if a bioassay uses insoluble ash as a marker.

Use of lactation curves for analysis of milk production data

Nonlinear equations were compared with categorical analysis to account for DIM effects on milk production. Five different models for lactation curves were evaluated. Derived from a multiphasic lactation curve, the selected lactation curve appeared to result in random residuals and performed more consistently than the multiphasic curve. Residuals from the fitting of lactation curves were then used for split-plot analysis (continuous model) to estimate treatment effects. Statistical performance of this model was compared with split-plot analysis based on a discrete model with regularly spaced intervals to account for DIM effects (discrete model). The fitting of lactation curves accounted for herd, lactation number, and interaction effects of herd and lactation number and accounted for 34.1 and 44.3% of variance among cows for primiparous and multiparous cows, respectively. The continuous model detected interactions of genetic and management factors with treatment of multiparous cows that were not detected by the discrete model. No statistically significant differences were detected between the two modeling approaches. The continuous model appeared to violate fewer assumptions regarding data distribution than did the discrete model, which reduced the risk of introducing bias during the estimation of treatment effects. The continuous model seemed to be more sensitive to subtle interactions of treatment and other factors.

Effects of rumen-inert fat on lactation, reproduction, and health of high producing Holstein herds

Two hundred twenty of 443 cows freshening between June 1989 and March 1990 in five commercial Holstein herds were fed .45 kg/d of rumen-inert fat from calving until 200 DIM. Control diets were fed as TMR and contained, on average, 3.7 to 4.8% supplemental fat (DM basis). Test herds had rolling herd averages of 9300 to 13,250 kg of milk. Production of 4% FCM and milk increased 1.01 (3.3%) and 1.50 kg/d (4.6%), respectively, for primiparous cows fed additional fat. Multiparous cows from four herds demonstrated no response; multiparous cows in one herd increased production of 4% FCM by 2.88 kg/d (8.2%), milk by 2.45 kg/d (6.4%), and milk fat by .14kg/d (10.6%) in response to additional fat. An explanation of response differences among herd for multiparous cows was not possible. For primiparous and multiparous cows, increased genetic potential increased treatment response. Increased body condition score at calving influenced treatment response of multiparous cows. Thinner cows produced more milk and less milk fat in response to additional dietary fat than did fatter cows. Most reproductive indices were unaffected by treatment. Cows receiving additional fat had lower, but nonsignificantly lower, incidences of most health disorders. Responses to rumen-inert fat by cows receiving high concentrations of dietary fat were marginal and were affected by body condition score at calving and by genetic potential.

Incidence and classification of early embryonic mortality in broiler breeder chickens

1. Unusually high early embryonic mortality (EEM) was observed in hatching eggs from broiler compared with white or brown table-egg breeders in Atlantic Canada. Broiler breeder EEM in Atlantic Canada was twice the EEM in broiler breeders from other areas of North America. 2. Comparisons of holding temperatures (18 and 30 degrees C) for 24 h after egg collection, in combination with a storage time of 0 or 7 d at 18 degrees C prior to incubation, were made using the criteria: embryo development (stage), and size at 0, 3, 6 and 9 d incubation, EEM, late embryonic mortality (LEM) and hatchability (HAT). 3. Stage of development of embryos, at 0 d incubation, was highest for eggs held for 24 h at 30 degrees C and stored for 7 d. Embryo stage, weight and length at 3, 6 and 9 d incubation were positively correlated. 4. Hatchability of fertile eggs was lowest (66.5%) for eggs held for 24 h at 30 degrees C and stored for 7 d and highest (87.2%) for eggs held for 24 h at 18 degrees C and stored for 0 d. Holding temperature and storage time significantly influenced EEM and LEM. 5. EEM classification differed for strain of breeder. In broiler breeders the majority of the EEM was at a relatively late stage of development (exhibiting an obvious blood ring with a visible embryo). In comparison, EEM from table egg breeders was distributed equally among three categories.

Influence of temperature, dietary energy, nutrient concentration and self-selection feeding on the retention of dietary energy, protein and calcium by sexually-maturing egg-laying pullets

1. On a daily temperature cycle of 25 to 35 degrees C and during the onset of lay, gross energy in droppings were increased significantly by 3 to 5%. There were no changes in energy metabolisability. Overall, less energy was excreted and energy metabolisability was improved on higher energy diets. 2. Crude protein and calcium losses decreased and their retention efficiencies increased with the onset of lay. Less protein and calcium were lost at the high temperature with corresponding increases in retention. Less protein and more calcium were lost on the higher energy diet. 3. Crude protein excretion was increased and calcium excretion reduced with self-selection feeding. Energy metabolisability and crude protein retention efficiency were reduced by this feeding practice.

Low dose ocular irradiation for diffuse choroidal hemangiomas associated with bullous nonrhegmatogenous retinal detachment

The authors describe five eyes in four patients with diffuse choroidal hemangiomas associated with progressive serous nonrhegmatogenous retinal detachment that were treated with low dose external beam ocular irradiation (1,250 to 2,000 cGy in multiple fractions). The subretinal fluid reabsorbed completely within 3 to 12 months of treatment in every case and there has been no reaccumulation in any case to date (median follow-up 14 months). Two of the patients have developed a focal posterior subcapsular radiation cataract in the treated eye (at 19 months and 66 months, respectively, after irradiation), but none of the patients has thus far developed radiation retinopathy. The authors discuss the potential benefits and risks of this form of treatment for choroidal hemangiomas with bullous retinal detachment.

Responses of sexually-maturing pullets to self-selection feeding under different temperature and lighting regimens

1. Pullets allowed to self-select nutrients from a protein concentrate and either a separate complete diet or cereal-based, energy-rich mixture showed preferences for protein and energy which varied in relation to the time of their onset of lay. 2. The selected protein:metabolisable energy (ME) intake ratio increased from 14 g protein per MJ of ME 2 to 3 weeks before sexual maturity to approximately 19 g protein per MJ of ME at and after sexual maturity. 3. This response to self-selection feeding was consistent with different temperatures, lighting patterns and dietary manipulations. 4. Egg mass output was improved by self-selection feeding at hot (25 degrees to 35 degrees C) temperatures in experiments 1 and 2 and at ambient temperatures in experiment 3. No beneficial response in egg mass from self-selection feeding was observed at cold (6 degrees to 16 degrees C) temperatures in experiment 1. 5. Providing 2 h of additional light during the dark (cool) part of the day, with or without 2 h of darkness in the middle of the extended light (hot) period, had no effect on the egg mass output of pullets at hot (25 degrees to 35 degrees C) temperatures.

Management of hemophilia in otolaryngologic surgery. A contemporary protocol

Hemophiliacs are well known to be among the high-risk groups for acquiring acquired immunodeficiency syndrome due to their frequent exposure to pooled blood products. We reviewed our recent experience involving hemophiliacs undergoing a variety of otolaryngologic surgical procedures. A protocol was developed to minimize the risks of hemorrhage through the judicious use of preoperative and post-operative coagulation replacement products. Modern hemostatic techniques, such as the use of the surgical laser, also had a role in lessening the incidence of bleeding problems. The relative risks of the various hemostatic products with regard to the transmission of communicable diseases such as acquired immunodeficiency syndrome and hepatitis were evaluated. Recent data suggest that heat treatment of factors VIII and IX concentrates eliminates the risk of acquired immunodeficiency syndrome transmission, and these heated concentrates should be used in preference to older products. Hepatitis remains a problem, but this risk may be reduced to some degree through immunization with hepatitis B vaccines that have recently been proved safe and effective.

Influence of dietary energy, nutrient density and environmental temperature on pullet performance in early lay

1. Alterations in dietary metabolisable energy (ME) concentration had a limited influence on food and nutrient intakes and egg mass output of hens in early lay kept at the prevailing air (10 degrees to 24 degrees C), cold (6 degrees to 16 degrees C) or hot (25 degrees to 35 degrees C) temperatures. 2. Energy intakes were not improved by increasing the dietary concentrations of nutrients other than energy. 3. At prevailing air and cold temperatures all dietary ME-nutrient density combinations allowed hens to meet the recommended daily protein intake but only hens fed the most concentrated diets were able to meet this recommendation at hot temperatures. 4. Even the highest intakes of ME and protein achieved at hot temperatures failed to increase egg mass output to the values attained on any diet at cold temperatures.

Inhibition of human placental aromatase by mefloquine

Aromatase activity of human placental microsomes was inhibited competitively by the antimalarial drug, mefloquine, but not by the related drug, chloroquine. In the absence of any drug, the Km for testosterone was 47.1 +/- 2.3 nmol/l (mean +/- SD, n = 2). In the presence of chloroquine 500 mumol/l, the Km remained unchanged (47.4 +/- 1.8 nmol/l (mean +/- SD, n = 2), whereas mefloquine inhibited competitively with respect to substrate with a Ki value of 72 +/- 4.2 mumol/l (mean +/- SD, n = 2).

Self-selection of calcium during the rearing and early laying periods of White Leghorn pullets

The ability of pullets to selectively consume calcium to meet the requirements of the rearing and early laying period was studied in White Leghorns. In the first of two experiments, 456 pullets were fed either an .89% calcium rearing diet (control) or a .35% calcium diet in combination with a separate source of 38% calcium chick-sized grit (calcium self-selection) from 35 to 126 days of age. Twenty-four pullets from each of these rearing treatments were selected for the second experiment at 112 days of age and were housed in individual laying cages. Rearing treatments were continued until 176 days of age with mash and grit consumption recorded daily for each pullet. From 177 to 225 days of age these pullets were fed a 3.50% calcium diet containing either ground limestone or oyster shell as a calcium source or a .35% calcium diet fed in combination with a separate source of oyster shell. Pullet calcium intake reflected the requirements for growth during the rearing period, calcium storage in the medullary bone 19 days prior to lay, and egg shell formation during the laying period; average calcium intake for these periods was 1.18, 2.08, and greater than 3.50%, respectively. Pullets also demonstrated the ability to compensate for rearing deficiencies by increased calcium consumption when fed oyster shell on an ad lib basis. Calcium consumption was found to be significantly higher on days when an oviposition occurred than when no eggs were laid. Mash consumption during the early laying period also reflected the reproductive status of the hen with the highest consumption on days when both oviposition and ovulation occurred, intermediate consumption when either oviposition or ovulation occurred, and lowest consumption when neither oviposition nor ovulation was detected.

Effect of quinoline-type antimalarial drugs on the binding of oestradiol-17 beta and progesterone by rabbit and human uterine cytosols

Rabbit and human uterine cytosol, prepared and tested in phosphate buffer, bound less oestradiol-17 beta or progesterone than cytosol from the same source prepared and tested in Tris-HCl buffer. Dissociation constants were the same in both buffer systems, and the difference in binding was due to a difference in the number of binding sites. Three quinoline-type antimalarial drugs, chloroquine, quinine and mefloquine, and the quinoline derivative, 4-(4'-hydroxy-1'-methylbutylamino)-7-chloroquinoline, increased the steroid binding capacity of phosphate-buffered cytosol to that of Tris-buffered cytosol, the optimal concentration of quinoline derivative being 1.4-1.6 mM. Tris (50 mM) increased the binding capacity of phosphate-buffered cytosol to that of Tris-buffered cytosol. The effects of Tris and quinoline derivatives were not additive. By gel chromatography and sucrose density gradient centrifugation it was shown that the molecular size and sedimentation behaviour of the oestradiol and progesterone receptors were not affected by the quinoline derivatives. Two types of binding site are proposed, one requiring the presence of low molecular weight, basic compounds. The uterine levels of chloroquine attained by normal pharmacological doses of the drug are potentially capable of influencing the binding of oestradiol-17 beta and progesterone in the uterine cytosol.

The effect of selection for fertility of frozen-thawed semen on spermatozoa oxygen uptake, motility and concentration, and ejaculate volume in the chicken

The response to 3 generations of selection for duration of fertility of frozen-thawed semen on fertility and hatchability of fresh and frozen-thawed semen, spermatozoa oxygen uptake, motility and concentration, and ejaculate volume was measured in a broiler line of chickens. The selected line, as compared to the control, had significantly higher levels for all fertility traits of frozen-thawed semen but not hatchabilities. For fresh semen, the lines differed only for duration of fertility. The only difference in semen quality traits was in oxygen uptake by spermatozoa of frozen-thawed semen. The differences between lines for the other parameters were not significant but were in a direction that supported the hypothesis that selection had resulted in improved reproductive capacity. All estimates of fertility within an ejaculate were positively correlated (P<0.01). Correlations between corresponding fertility estimates of fresh and frozen-thawed semen were positive, low and generally non-significant. The proportion of variation as determined by stepwise regression, in fertility estimates accounted for by the measurements of oxygen uptake and motility of fresh and frozen-thawed spermatozoa, ejaculate volume and spermatozoa concentration ranged from 12 to 19 percent.

Synthesis of vitamin B6 by a mutant of Escherichia coli K12 and the action of 4'-deoxypyridoxine

Mutants of Escherichia coli K12 blocked in the oxidation of pyridoxine 5'-phosphate ('Oxidase' mutants) excreted pyridoxine at an initial rate of 19 pmol h-1 (10(8) bacteria)-1, i.e.0.6 nmol h-1 (mg dry wt)-1, when starved for pyridoxal. Glycolaldehyde, L-phosphoserine, DL-serine and, to a lesser extent, L-leucine stimulated the rate of pyridoxine excretion, but there was no significant stimulation by 2'-hydroxypyridoxine. 4'-Deoxypyridoxine inhibited or stimulated growth of the "Oxidase' mutant, depending on the relative concentrations of added pyridoxal and 4'-deoxypyridoxine. It was concluded that stimulation of growth by 4'-deoxypyridoxine was due to its conversion to pyridoxal.

The isolation and characterization of three types of vitamin B6 auxotrophs of Escherichia coli K12

Approximately 500 vitamin B6 auxotrophs were isolated from 18 independent cultures of Escherichia coli strain CR63. None grew in minimal medium supplemented with 2'-hydroxypyridoxine. Eighteen auxotrophs which had arisen independently were further characterized. All of them were defective in vitamin B6 synthesis rather than in an aminotransferase involved in vitamin B6 utilization. Two different phenotypes were recognized: 'Oxidase' mutants which grew only when supplied with pyridoxal or pyridoxal 5'-phosphate and 'Pre Pn' mutants which would also grow with pyridoxine or pyridoxine phosphate. "Oxidase' mutants were confined to a single linkage group, but data from interrupted mating experiments established that 'Pre Pn' mutants fall into two linkage groups which are possibly identical to pdxA and pdxB. All mutations in the in the pdxA region were allelic rather than located in two closely linked genes.

The mode of condensation of aspartic acid and dihydroxyacetone phosphate in quinolinate synthesis in Escherichia coli

Dihydroxy [3-14C]acetone phosphate was prepared enzymatically from [1-14C]glucose and use as a substrate in a partially purified quinolinate synthetase system prepared from Escherichia coli mutants. Carbon-by-carbon degradation of the resulting [14C]quinolinate showed that 96% of the 14C was located in carbon-4, indicating that carbon-3 of dihydroxyacetone phosphate condenses with carbon-3 of aspartate in quinolinate synthesis in E. coli.

The conversion of 3-Hydroxy-2,4,5-trihydroxymethylpyridine into pyridoxine by Kloeckera apiculata

Kloeckera apiculata, a vitamin B-6-dependent yeast, grows in the presence of 3-hydroxy-2,4,5-trihydroxymethylpyridine in vitamin B-6-free media. On a molar basis the growth-promoting activity of this compound is approximately one-tenth that of other forms of vitamin B-6. [G-3H]3-Hydroxy-2,4,5-trihydroxymethylpyridine is converted into radioactive vitamin B-6 compounds of the same specific radioactivity by growing cultures of K. apiculata.